An elevator hall in a building is provided with a hall door serving as a gate to an elevator car. The hall door is usually shut securely to block the communication between the elevator hall and the side of a hoistway in which the elevator car travels upwardly and downwardly, and is open and closed synchronously with the opening and closing of the elevator car when the elevator car reaches the elevator hall.
The hoistway in which the elevator car is vertically movable is provided so as to vertically extends from the lowest floor to the highest floor of the building. In the hoistway, there is a governor rope hanging from a sheave, and a counterweight vertically movable in the opposite direction to the moving direction of the elevator. The wall of the hoistway and the elevator car allow a rather large space.
Therefore, since it is not completely possible to deny the possibility that the hoistway serves as a chimney extending in vertical directions when a fire occurs in the building, the elevator hall door is formed of a refractory material, such as a metal, so that the fire and smoke can hardly enter into the hoistway.
If a building fire occurs, there are some cases where the elevator hoistway serves as a passage for smoke and fire to sequentially introduce to the upper floor, causing further increased damage by the spread of the fire. The reason why smoke and fire enter into the hoistway is that the elevator hall door arranged on the elevator hall falls off due to the damaged deformation caused by heat so that the elevator hall gate serves as a smoke inlet.
FIG. 11 shows a elevator hall door which is utterly deformed by being exposed to heat caused by a fire on an elevator hall. In FIG. 11, reference number 1 denotes a door frame 1 which is fixed to a wall 2, and reference number 3 denotes an elevator hall door In FIG. 11, the left side is a hoistway, and the right side is an elevator hall. Reference number 4 denotes a header case which is fixed to the top side portion of the entrance of the wall 2, and reference number 5 denotes a sill which is fixed to a gate floor 6. A hanger roller 7 is supported on a hanger 8 which is mounted on the top end portion of the elevator hall door 3. On the other hand, a hanger rail 9 with which the hanger roller 7 engages so as to be capable of rolling thereon is mounted on the header case 4, and the elevator hall door 3 is open and closed while the hanger roller 7 rolls on the hanger rail 9. On the bottom end portion of the elevator hall door 3, a guide shoe 10 sliding in a guide groove of the sill 5 is mounted.
As shown in FIG. 12, the door panel of the hoistway door 3 comprises a surface board 11 constituting a design surface, a back board 12, and a reinforcing member 13 for reinforcing them.
If the elevator hall door 3 is exposed to heat when a fire occurs in the building, the door panel of the elevator hall door 3 starts to be gradually deformed so as to be warped as shown in FIGS. 11 and 12. If the elevator hall door 3 is further exposed to heat, the elevator hall door 3 falls away from the hanger rail 9 and the sill 5, allowing fire and smoke to enter into the hoistway from opening space of the elevator hall, so that there is the possibility of spreading the fire to upper floors.
To taking countermeasures for preventing such a hazardous situation, there are know measures to utilize elongated holes, which are provided in connecting portions of the back board 12 to the surface board 11 and the reinforcing member 13 for allowing them to slide in vertical directions, to absorb the difference in heat expansion between the back board 12 and the surface board 11 and reinforcing member 13. These elongated holes enable the door panel to suppress the deformation to prevent from falling off.
However, although the above described conventional elevator hall door can absorb the difference in elongation in vertical directions between the back board 12 and the surface board 11 and reinforcing member, the door panel of the elevator hall door is restricted in depth and lateral directions, so that it is insufficient to suppress the deformation of the door panel even if the deformation is suppressed to some extent.
In addition, all of component parts of the door hanger apparatus of the elevator hall door 3 are difficult to be formed of fire resistant materials for structural reasons. For example, the hanger roller on the reverse side of the header case 1 on the elevator platform is provided with a cushioning material, such as a plastic, at least on the outer peripheral surface thereof in order to ensure the quietness of operation of the elevator hall door.
Although the cushioning material itself does not easily melt by using a fire-resistant plastic material or the like, it is considered that the cushioning material melts due to heat of a high temperature during a fire in a special case beyond expectations.
If the melted cushioning material falls while it has heat of a high temperature, if a part thereof enters the hoistway from the elevator hall door 3, and if a lubricating oil or the like exists in the hoistway in the vicinity thereof, it is considered that the melted cushioning material takes fire to cause a secondary fire.
It is therefore an object of the present invention to eliminate the above described problems in the prior art and to provide an elevator hall door capable of suppressing the deformation of a door panel to prevent the falling of the elevator hall door and to prevent smoke and fire from entering into a hoistway to prevent the spread of the fire, by preventing a back board, a surface board and a reinforcing member from being restricted in all directions when a differential thermal expansion occurs between the back board, the surface board and the reinforcing member.
It is another object of the present invention to provide an elevator hall door hanger apparatus which is capable of preventing a cushioning material of a hanger roller from entering a hoistway to prevent the spread of the fire even if the elevator hoistway door is heated to melt the cushioning material of the hanger roller during a fire.
In order to accomplish the above described objects, according to a first aspect of the present invention, there is provided an elevator hall door for closing and opening an entrance on an elevator hall, said elevator hall door comprising a door panel comprising a surface board facing a elevator hall, a back board facing a hoistway, and a reinforcing member for reinforcing said surface and back boards; and a connecting member configured to connect said back board to said surface board or said reinforcing member, wherein at least a part of said connecting member is capable of losing the force of constraint against said surface board or said reinforcing member on high temperature conditions during a fire.
According to this aspect of the present invention, if the difference in elongation due heat between the surface board and/or reinforcing member, which are exposed directly to heat of a high temperature by a fire in a building, and the back board increases, the door penel intends to be deformed. However, the connecting member is broken or melts by the high temperature to lose the force of constraint, so that the surface board and the reinforcing member are in an elongated state without constraint in specific directions. Thus, it is possible to prevent the whole door panel from being deformed.
According to a preferred embodiment of the present invention, the connecting member comprises a steel rivet of a steel product for connecting one end portion of the door body, and a low-melting-point or low strength aluminum rivet of aluminum for connecting the remaining portion of the door body to be used as the connecting member. Thus, even if the aluminum rivet is disengaged, the steel rivet holds the surface board and/or the reinforcing member to inhibit these members from falling.
The connecting member may comprise a rivet having a smaller head than a rivet hole which is formed in a connecting portion of the back board, and a resin or rubber washer which is provided between the head of the rivet and the back board, or may comprise a bolt, and a resin or rubber nut which forms a counterpart to the bolt.
According to a second aspect of the present invention, there is provided an elevator hall door hanger apparatus for suspending a elevator hall door, which has a front face facing an elevator hall and a back face facing a hoistway of the elevator, in an entrance on the hall, said door hanger apparatus comprising a hanger member having a substantially L-shaped cross section, said hanger member comprising a short piece which is fixed on the upper portion of said door, and a long piece which rises along the back face of said door; a plurality of hanger rollers which are rotatably mounted on said hanger member and each of which has a cushioning member at least on the outer peripheral surface thereof; a guide rail which is supported by the entrance on the hall so as to extend in horizontal directions to guide said plurality of hanger rollers; and penetration preventing means configured to prevent material of said cushioning member, which melts on high temperature conditions, from flowing along said hanger member to enter into said hoistway.
According to this aspect of the present invention, even if the elevator hoistway door receives heat during a fire to melt the material of the cushioning material of the hanger roller, the cushioning material entering inhibiting means causes the melted material to flow toward the platform on the side of the front face of the hoistway door to prevent the melted material from flowing to the hoistway on the side of the back face, so that it is possible to prevent the melted material from taking fire to cause the secondary spread of the fire.